The present invention relates to a coated foam insulation sheet and, in particular, to a coated foam insulation sheet, especially suited to be a duct liner, with a relatively smooth tough elastomeric coating on one or both of its major surfaces, and the method of making such a coated foam insulation sheet.
Foam sheets are used as duct liners to line air ducts and the like, especially, for applications such as a clean room air supply, where fibrous insulations can not be used to line the air ducts. In such applications, airborne dust and particles, including viruses, bacteria, pathogens and other infectious or contaminating agents, tend to collect or accumulate in any surface irregularities present on the interior surface of the duct liner and such surface irregularities increase the frictional resistance to air flow through the air ducts. Thus, there has been a need to reduce surface irregularities on such duct liners and provide a smooth tough interior surface on foam insulation sheets used as duct liners, especially open cell foam insulation sheets.
U.S. Pat. No. 4,990,370, On Line Surface and Edge Coating of Fiber Glass Duct Liners, issued Feb. 5, 1991 (hereinafter "the '370 patent") and U.S. Pat. No. 5,211,988, Method for Preparing a Smooth Surfaced Tough Elastomeric Coated Fibrous Batt, issued May 18, 1993 (hereinafter "the '988 patent") disclose coated fibrous batt duct liners and apparatuses for and methods of making such coated fibrous batt duct liners. The disclosures of the '370 patent and the '988 patent are hereby incorporated herein by reference in their entirety.
While the disclosures of the '370 patent and the '988 patent have been publicly available for over seven years and over five years respectively, there has remained a need for foam insulation sheet duct liners with smoother interior surfaces to reduce the accumulation of infectious agents and other contaminates on the interior surface of such duct liners and to reduce the frictional resistance to air flow through the air ducts.